Patent GB-1402673-A (GB)
Title: Brake apparatus for motor vehicles
IPC: F16D63/00
Filed: 1973-05-11
Abstract: 1402673 Combined internal shot drum brakes and spot-type disc brakes AUTOIPARI KUTATO INTEZET 11 May 1973 [17 May 1972] 22602/73 Heading F2E A drum and a disc both rotate with the hub of a vehicle wheel; a caliper associated with brake pads for the disc is connected directly or indirectly with each brake shoe for the drum so that on actuation of the disc brake the brake pads, entrained by the disc, act either directly or through the calipers to apply the brake shoes to the drum. In Figs. 1 and 2, the cylinder 41 of an hydraulic actuator is mounted in a sleeve 40 secured to one of the webs 25 of a brake shoe 23, this web, the other web 26, the cylindrical platform 24 and a stiffening member 27 forming a caliper. On application, piston 43 moves a brake pad 31 and an axially slidable disc 14 against an axially-fixed brake pad 30 to brake the disc. The brake drum 10, Fig. 1, is assumed to be rotating counter-clockwise, so the left hand brake shoe 23 is urged, by disc-pad friction leftwards about a pivot at its other end until the clearance h is taken up. Shoe 23 is linked to shoe 23a, Fig. 1, by an automatic slack adjuster 36 for the shoes which yields in tension to allow for friction-lining wear. The shoes are also connected to a spring 35. Shoe 23a is applied by disc-entrained brake pads (not shown) diametrically opposite, in the drum, to those described above. When the direction of rotation is reversed, the movement of shoe 23 to the right caused by entrainment, and not less in amount than in the former case, is transmitted by adjuster 36, which does not change length in compression, to shoe 23a. Similar action occurs at the diametrically-opposite location in the drum. Each shoe is pivoted, at that end which does not accommodate the disc brake pads, about a fixed bolt, e.g. 18, Fig. 1. In Figs. 3 and 4, a disc 64 is again axially slidable, by grooves 62a on a rotary ribbed sleeve 62. A brake holder 63 is rigidly secured to a fixed bridge 53, and a pivot bolt 65 is located against axial movement in the brake holder 63 by a ring 66 and a ball 66a. A brake caliper 68 is pivoted on bolt 65 with its upper surface between the bolt and the holder 63. Pivoted on sleeves 69, 69a on bolt 65 are lugs or webs 72 of brake shoe 71 (on the right in Fig. 3). The thus pivoted end of brake shoe 71 is attached by a spring 76 to the non-pivoted end of brake shoe 71a. Brake pads 85, 85a, Fig. 4, are slidable in bores in brake caliper 68, and brake pad 85 is moved for disc-brake action by a lever 91 having an extension 92 bearing against a cut-out 90 of caliper 68, the lever acting on an automatic slack adjuster 88 communicating with brake pad 85 and being driven by a compressed-air actuator 96 or a spring (not shown), normally held off by compressed-air, in actuator 97. Pivoting of the caliper by disc-pad entrainment on braking causes involute surface 78, Fig. 3, on the caliper 68 to move shoe 71a, by contacting involute surface 77, against drum 60. A slack adjuster 81 for the shoes, yieldable only in tension, is located between a caliper extension 79 and a bolt 80 on shoe 71. All these features are repeated for the other ends of the shoes.